Microsoft Notification Protocol

Mobile Status Notification Protocol (MSNP, which is not an acronym for "Microsoft Network Protocol" as is often believed) is the protocol employed by MSN Messenger and other clients like Trillian and Windows Messenger to communicate with the MSN Messenger switchboard servers.

Version History

MSNP1

MSNP2

Made available to developers in 1999 in an Internet Draft

MSNP3

MSNP4

MSNP5

MSNP6

MSNP7

MSNP8

Minimum version of the protocol accepted by the switchboard servers, rendering older and obsolete clients inoperable with their servers, forcing users to upgrade clients.

Currently the only "official" MSN Messenger client that still uses this protocol is Windows Messenger 4.6 through 4.8 and the 5.x series.

This protocol supported Windows Messenger-to-Windows Messenger webcam and voice capabilities.

MSNP9

Version of the protocol starting with MSN Messenger 6, adds support for display pictures, frame-by-frame webcam (rather than a traditional stream like Windows Media Player's WMV format and an improved voice system, as well as improved NAT traversal for file transfers.

MSNP10

Employed in MSN Messenger 6.1, after Microsoft decided to switch the internal configurations in October 2003. However, it was not a big overhaul, and most of the external features remained the same.